Shared memory multiprocessing implementation of resolution-of-the-identity second-order Moller-Plesset perturbation theory with attenuated and unattenuated results for intermolecular interactions between large molecules

We examine the second-order MOller-Plesset perturbation theory energy under the resolution-of-the-identity approximation (RI-MP2) and present an improved algorithm for single-node, multi-threaded computation. This algorithm is based on shared memory parallelisation of the rate-limiting steps and an overall reduction in the number of disk reads. The requisite fifth-order computation in RI-MP2 calculations is efficiently parallelised within this algorithm, with improvements in overall parallel efficiency as the system size increases. Fourth-order steps are also parallelised. As an application, we present energies and timings for several large, noncovalently interacting systems with this algorithm, and demonstrate that the RI-MP2 cost is still typically less than 40% of the underlying self consistent field (SCF) calculation. The attenuated RI-MP2 energy is also implemented with this algorithm, and some new large-scale tests of this method are reported. The attenuated RI-MP2(terfc, aug-cc-pVDZ) method yields excellent agreement with benchmark values for the L7 database (R. Sedlak etal., J. Chem. Theory Comput. 2013, 9, 3364) and 10 tetrapeptide conformers (L. Goerigk etal., Phys. Chem. Chem. Phys. 2013, 15, 7028), with at least a 90% reduction in the root-mean-squared (RMS) error versus RI-MP2/aug-cc-pVDZ.